Method and means for forging billets



aml'h m, 1331 M. w. KELLOGG 1,793,742

METHOD AND MEANS FORFORGING BILLETS Filed Aug. 12, 1927 3 Sheets-Sheet. l

EJ-vwentoz Wm M. w. KELLOGG 1,793,742

METHOD AND MEANS FOR FORGING BILLETS Filed Aug. 12, 1927 3 Sheets-Sheet. 2

gvwemtoz March 31, 1931. w, KELLOGG 1,798,742

METHOD AND MEANS FOR FORGING BILLETS Filed Aug. 12, 1927 3 Sheets-$heet 3 vwemtoz Patented Mar. 31, 1931 UNITED STATES PATENT OFFICE MORRIS W. KELLOGG, OF BROOKVILLE,

new roux, nssrenon 1 0 THE m. w. KELLOGG COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE METHOD AND MEANS FOR FOBGIN G IBILLETS Application filed August 12, 1927. Serial No. 212,411.

The invention relates to a method and means for forging hollow articles such as hollow cylinders and tubes, and in particular to an improved die to be used in forging such articles.

The invention has for an object the forging of tubular articles from hollow billets or ingots in a simple manner and with fewer heating operations between the forging steps than have been required in the forging processes customarily used.

A further object of the invention is to increase the speed of production.

7 A still further object of the invention is to insure greater accuracy in the dimensions, both external and internal, of the forged tubular articles formed.

Another object of the invention is to pro vide a die which may be readily adjusted for operation on billets or ingots of different internal diameters, and which is associated with means for bringin about relative movement, in either a longitudinal or circumferential direction, or both, between the die and the billet or ingot being worked.

Still another object of the invention is to produce rolling contact between an internal die and the internal surfaces of the "walls of the article being formed in a longitudinal direction as well as in a circumferential direction, so as to density the metal and to impart to it a fibrous structure with a minimum expenditure of power.

Other objects will appear as the description proceeds.

According to a preferred form of the pres-- ent invention, a hot tubular blank, for example, a billet or ingot which has been cast, forged or otherwise formed, is inserted in a die which hasan internal sha e and size corresponding to that desired or the exterior of the resulting tubular article, and then forged outwardly against the internal surfaces of the die, by means of a rotatable internal die. The tubular blank preferably has at the beginning of the forging operation an outside diameter substantially the same as the internal diameter of the die, in which case the tubular blank will tend to elongate as the internal diameter of the blank is increased the axis of the die so as to permit of under the forging and expanding action of the internal die. However, it is within the scope of the invention to forge a tubular blank having an outside diameter smaller than the internal diameter of the outside die by suitably supporting the blank in centered relation to the external die and then forging and expanding it outwardly against the internal surfaces of the outside die by means of the rotatable internal die. It is to be understood that the term expanded? as used in the claims is intended to cover a forging operation which is carried out in either of the ways above-mentioned. The internal die preferably comprises a plurality of rollers spaced about the periphery of the die head and adapted to be adjusted toward and away from the forg- 1g of pipes and other tubular articles of different internal diameters without the necessity of changing die heads, and also to permit of the adjusting of the die to the gradually increasing diameter of the article being forged as the metal is compacted and expanded under the pressure of the rollers. Means for imparting relative ment between the internal die and the external die or billet holder, as well as a rotating movement either to the external or the internal die, is also provided. The rolls are preferably so mounted in the die head as to cause them to have a rolling action on the metal in a longitudinal direction well as in a circumferential direction so that in passing through the billet being forged they describe helical or spiral paths.

For a more complete understanding of the invention reference will now be had to the accompanying drawing forming a part of this specification, and in which:

Fig. 1 is an elevational view partly in section showing an apparatus by which the forging operation may be performed;

Fig. 2 is an end View looking from the right of Fig. 1;

Fig. 3 is a plan view of the internal die;

Fig. 4 is a longitudinal section of the internal die;

Fig. 5 is a part section and part elevation on the line 55 of Fig. 3;

longitudinal move-' Fig. 6 is an end elevation of the die shown in Fig. 3 viewed from the right hand side of the figure;

In Figs. 1 and 2 of the drawing there is shown a hollow billet or ingot 10 clamped within a cylindrical die or billet holder 11. The die 11 is illustrated as split but may be solid. Itis secured in a stationary position between the two jaws 12 and 13 of a press, the jaws being forced together by a hydraulic cylinder 14 or other suitable means and are preferably positively held in closed position by suitable mechanical locking means. Such means may, as shown in Figs. 2 and 8, consist of bolts 41, passing through holes in'cooperating flanges 42 carried on the jaws 12 and 13, and provided with slots 43 at one end adapted to receive wedges or keys 44. The lower jaw is shown as clamped to a base or bed-plate 15 although it is to be understood that either jaw may be fixed and the other movable. Another die 16, preferably adapted to rotate, is disclosed in operative relation to the billet and is adapted to forge the billet outwardly against the internal surface of the outer die 11 and to cause the billet to elongate. The die 16 is shown as provided with three equally spaced rollers 17 mounted in bearings 18 carried by the die head 19.-

ahead of them, as would be the case if the rollers were mounted on axes parallel with that of the die head. It is believed that this feature is important, and that failure properly to take into account the difiiculties which it overcomes was one of the reasons why earlier attempts to forge hollow articles by means of an internal rotating die head have not proven successful. .W'lrile the angle at which the rollers may be mounted may be varied over a considerable range, depending upon the rate of feed, speed of rotation and size of the tubular blank being worked, very satisfactory results are obtained if the rollers are mounted at an'angle of approximately three degrees to the axis of the die head when working tubular blanks having an inside diameter of about one and a half feet.

In order to adjust the die for use in forging billets of different internal diameters or to progressively enlarge the die as the inter nal diameter of the tubular article being formed is increased due to the forging action of the rollers, means for moving the respective rollers toward and away from the axis of the die head is provided. Various means for so adjusting the rollers will suggest themselves. In the drawing I have shown-members 20, wedge-shaped in longitudinal section and having the general form'of a frustrated prism. These members are carried by a right and left hand screw 21. The screw. 2l-is shown as having a suitably shaped end portion 22 adapted to be engaged by suitable means, either power or hand; operated, for

turning. respective rollers 17 normally are held in working engagement with the members 20 by suitable means, and upon turning the screw 21 the members 20 are caused to move toward or away from one another along the screw 21 and to force the bearing supports 23 and the rollers 17 carried thereby away from or toward the axis of the die head as the case may be. As means for holding the bearing supports 23 in contact with the members 20, the bearing supports in F ig. 7 are shownas provided with dovetailed portions 45 fitting in grooves 46 in the members 20. Other forms of means for retaining the bearing supports in operative position on the die will suggest themselves to those skilled in the art.

Suitable means for lubricating the bearings 18 of the respective rollers 17 may be provided, if desired. Likewise water cooling means may be provided to prevent excessive heating of the roller mountings and the adjustable elements of the die head.

According to the embodiment of the invention shown in the drawings, oil is led to the bearings 18 of the respective rollers 17 through the flexible metal tubes 24 and dis charged into ducts 25 formed in the walls of the bearings 18 and discharging to the bearing surfaces through openings 26. The flexible tubes 24 are connected to a source of oil supply not shown by means of pipes 27, the latter being positioned in the hollow shaft 28 supporting the die head 19. According to the showing in the drawing, oil is led to those bearings at, the end of the die head remote from the shaft 28 by means of a passage 29 in one of the bolts 29a securing the die head to the supporting shaft 28, said passage being connected to one of the pipes 27 atone end and at the other end discharging through a connection 30 to a header 31 which connects with flexible tubing 24 leading to those bearings of the rollers adj aoent thereto. In lieu of providing a passage for oil in one of the bolts 29a a separate pipe or tubing may be used.

The die head structure illustrated in the drawing is shown as provided with means for cooling the roller mountings and the adjustable elements of the die head. Cooling is brought about by connecting the hollow shaft 28 to a suitable source of water or other cooling fluid not shown. For cooling those bearings and parts of the die head adjacent to the shaft 28, pipes lead from the hollow shaft 28 and are coupled to flexible The bearing supports 23 for the inetal tubes 33 which in turn are connected to the bearing supports 23 and discharge through passages therein to ducts 34 formed in the bearing walls. Such ducts 34 are shown as helically encircling the bearings and discharging finally through the openings 35. As the water or other fluid cooling medium is ordinarily supplied under pressure, it will be caused to impinge upon a portion of the roller which is out of contact with the metal being forged, and serve to maintain the temperature of the roller at a point permitting of satisfactory operation. For those bearings at the end of the die head remote from the hollow shaft 28, a pipe 36 con nects with the hollow shaft 28 at one end and at the other end connects with a passage 29 in one of the bolts 29a which in turn communicates through suitable pipe connections 37 with a header 38 in the same manner as the oil is led to the header 31 above mentioned. Instead of providing a passage in one of the bolts 29a a separate connecting pipe may be used. Flexible metal tubes 33 lead from the header 38 to ducts 34 in the several cured to the die head by means of bolts 40.

. The plate 39 is shown as provided with a central opening 41 to permit of access to the end portion 22 of the screw 21 for adjusting the position of the rollers 17.

In the construction shown in the drawing rotary motion is imparted to the die 16 by mounting the hollow shaft 28 on one side of a rotating disk or counterpoising member 47 carried b a shaft &8 journalled in a supportingmem er 49. The supporting member 49 is shown as adapted to be moved longitudinally by means of a screw or worm 50 mounted in the bed plate 51.

It will be understood that the inner die may perform forging operations on the billet "l jvhen moving in either direction through the illet.

The method and apparatus disclosed herein are particularly applicable in producing tubes having a relatively large diameter, that is from 16" upwards, while at the same time applicable in forming smaller tubes, and whereas wrought tubes of such large sizes have heretofore required long and tedious forging operations and frequent re-heating of the metal, and great care has been required in order to insure a uniform product, by the use of the described apparatus it is possible to produce such tubes having uniformly high strength in an expeditious manner and without resorting to such frequent reheating of the metaldue to the more rapid working of the same. The present apparatus lends itself particularly to use in combination with processes in which the billet is cast centrifugally, in which case the billet may be transerred from the casting mold to the billet holder or outer die while still hot or with a minimum amount of re-heating, and then forged by the inner rotating die until it has cooled below the desired working temperature.

For some purposes it may be desired to cold work tubular metal articles, and it is to be understood that the use of the present method and apparatus for such purpose is not precluded.

While the invention has been described with particular reference to the embodiment shown in the drawing, it is to be understood that many and various changes in the mechanical structure and lay-out may be made without departing from the scope of the invention which is not to be deemed to be limited other than as indicated in the appended claims.

I claim:

1. The recess which comprises inserting a hollow bi let in a cylindrical die, clamping it sufficiently tightly in the die so as to pre vent movement thereof with respect to the die except that due to elongation of said billet, bringing a second die into operative relation with the billet in the die, repeatedly causing one die to move relatively to the other in a rotary and longitudinal direction so as to advance the second die through the bore of the billet and to impart rolling pressure to the material of the billet both in a rotary and a longitudinal direction, to force the said mate rial of the billet against the inner surfaces of the first mentioned die and to expand and elongate the billet, and between passes of the second die through the billet adjusting the second die to inscribe a larger circle of revolution by those portions of the die which contact with the billet being worked.

2. The process of forming tubular articles which comprises centrifu ally casting a hollow billet, inserting the b1llet while still hot from the casting operation in a cylindrical die in operative relation to a second die, causing the second die to rotate and to advance through the bore of the billet and to impart rolling pressure to the material of the billet both in a rotary and a longitudinal direction to force the said material against the inner surfaces of the first mentioned die and to expand and elongate the billet, adjusting the second die to the bore of the billet as it becomes enlarged under the working, and repeating the passes of the second die through the billet until the billet has cooled to any desired temperature.

3. The apparatus comprising a die adapted to hold a hollow billet, a second die, means for causing relative movement between the dies both in a rotary and a longitudinal direction to advance the second die through the bore of the billet, means carried by the second die adapted to irnpart'rollingpressure to the billet both in a-rotary and a longitudinal direction to force the material of the billet against the inner surfaces of the first mentioned die and to expand and elongate the billet, and means for quickl adjusting the size of the second die to a size suitable for the bore of the billet being worked.

In testimony whereof, I have signed my name to this specification this 11th day of 15 August, 1927.

- MORRIS W. KELLOGG.

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